A friend of mine is getting involved with a group called the United Church of God. Does anyone know anything about them? Are they a cult?
Yes, they are definitely a cult associated with the teachings of Herbert Armstrong. I used to be an Armstrongite, and am now an evangelical Christian so I am very familiar with their teachings. Armstrongite groups include Restored Church of God, United Church of God, Living Church of God and various other groups with "Church of God" in their name (although not all Church of Gods are Armstrongite groups).
They deny the Trinity doctrine, instead claiming that God is currently two separate beings, the Father and Son, and that resurrected believers will become fully God. They teach that they are the "only true Church" and that the rest of those who call themselves Christians are false, "so-called" Christians who are part of the Satanic system called the "Great Prostitute" of Revelation 17. The primary characteristic of this Great Prostitute is that she doesn't observe the Saturday Sabbath. Anyone who does not observe the Saturday Sabbath is under the "Mark of the Beast" or will be under it during the Great Tribulation.
Salvation is basically about being a god in embryonic form, with abortion assured for those who don't develop sufficient character to be trusted with the full powers of godhood.
Their doctrines are a product of the mind of Herbert Armstrong. He was a very divisive, proud and vain man, who considered himself to be both an Apostle and Prophet, in the same sense as the NT apostles and OT prophets. He considered himself to be the Elijah to Come. UCG, in particular, attempts to divorce themselves from Herbert Armstrong, but they teach identical doctrines. I consider Armstrongite doctrine to be the National Enquirer mentality; their focus is on the sensational like prophetic speculation, and it is geared largely toward discrediting Christianity, which they consider to be a Satanic counterfeit.
Their mentality is very like the mentality of the National Enquirer, focusing on sensational issues like prophecy and adopting a conspiracy theory mentality of church history. Hislopite beliefs and British Israelism are a part of their childish belief system.
Regarding their politeness, politeness is not the measure of a cult. Unorthodox teaching is the measure we should use. The essentials, such as the deity of Jesus Christ, the Triune nature of God, justification by faith, the bodily resurrection, the virgin birth, and the judgment of the righteous and unrighteous are doctrines we should measure groups against.
They also deny the bodily resurrection and the concept of biblical regeneration, and justification by faith alone. Their theology is very fear and condemnation oriented.
I strongly warn against their teachings, and encourage anyone who is looking for a good, sound source of teaching to attend an Evangelical Free Church of America, Christian And Missionary Alliance, or various other evangelical church congregation.
I would be glad to answer questions about them if anyone is seriously considering joining them. I did an overview on their teachings on YouTube. Look for the channel Exposing United Church of God. It is not the best quality video, and I likely will try to refine it in the future.